TM 5-3820-256-10
to connect the kelly to the drill string. Use the break-out wrench on the drill string and hold a back-up
on the kelly. Torque the connection.
(h)
Raise the kelly slightly, remove the break-out fork, and lower the drill string until the kelly drive
bushings are engaged in the rotary table.
NOTE
Using a level vertically against the kelly, check that the hole is being drilled straight down and is not
drifting.
(i)
Begin mud circulation, table rotation, and lower the kelly to resume drilling. Drill down kelly, using
pulldown, if required, as before.
(j)
Add more drill pipe using the same connection procedures described above until the hole is drilled to
required depth.
c. Mud drillinq techniques.
(1)
Mud mixing.
(a)
In order to carry the cuttings to the surface, especially when at greater depths, the mud must be kept at
certain weight and viscosity levels. Additives, such as bentonite, are entered into the circulation
system to accomplish this. Refer to FM 5-166 for more information about mud treatment.
(b)
Install the mud mixing hopper assembly on the water hose line. Slowly add bentonite into the mud
hopper in accordance with instructions on the bag. Mix the material thoroughly and allow sufficient
time for it to attain final consistency. Continue mud circulation while testing the mud for the correct
weight and viscosity.
(2)
Weight/density test.
(a)
Use a mud balance to determine the density of drilling mud in pounds per gallon. Remove the lid and
fill cup to top with a fresh mud sample. Tap the cup to cause any trapped air bubbles to break out.
(b)
Replace lid and tighten until firmly seated, making sure some mud seeps out the vent hole. Wipe any
mud off the outside of the balance. Place the balance on the base with the knife edges on the fulcrum
rest.
(c)
Move the balance rider until the level indicates balanced. Read the mud weight (in pounds per gallon)
indicated at the edge of the rider nearest the fulcrum. Record the mud weight in the drilling log.
(3)
Mud viscosity test.
(a)
Use the marsh funnel viscometer, a graduated cup, and a stop watch to determine the viscosity of the
mud. Hold the funnel upright with
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